This invention relates, generally, to an improved harp and, in particular, to an improved spindle for harps for substantially reducing or eliminating friction between the spindles and the harp's action plates in which the spindles are secured and for eliminating "freezing" of the spindles.
All harps have a disc associated with the respective ones of the harp's strings. These discs each carry two disc prong which are integrally formed therewith and are in spaced-apart relationship, such that when the disc is rotated, the disc prongs will grab the string tightly enough for the string to sound clear and not buzz when played. The discs each are affixed to one end of the spindle which is disposed between and supported by a pair of spaced-apart action plates secured to the neck of the harp. The spindles are rotatably operated by the linkage assemblies which comprise the harp's action and are operated respectively by one of the harp's foot pedal assemblies. The spindles, in turn, rotatably operate the discs which are affixed to them to grab the strings which are associated with the respective one of them.
The action plates between which the spindles are carried are of brass, and the spindles generally are of stainless steel or other metallic material which is of sufficient strength to rotatably support the linkage assemblies and which will create the least amount of friction as possible with the brass action plates when the spindles are rotatably operated. The harp can include as many as 90 such spindles and each linkage assembly includes a number of them. Any friction associated with the spindles included in any one linkage assembly has an accumulative affect when a foot pedal is operated, hence the more friction, the more difficult it is to operate the foot pedals.
Over the years, the design of these spindles has remained basically the same in spite of the fact that the friction between the spindles and action plates always has been a problem. In many cases, the spindles "freeze up" and cannot be rotated at all. Attempts have been made to eliminate this problem, yet none have provided a viable solution. For example, in many cases, special lubricants have been used and while initially the special friction is reduced, constant maintenance is required and the spindles must be relubricated. In extreme cases, hydraulic systems have been incorporated into the harp's action. These systems do not reduce the friction but simply reduce the effort required to operate the foot pedals. With these arrangements, the possibility of damaging the linkage assemblies and the pedal rods is greatly increased should one or more of the spindles "freeze up". Accordingly, none of these solutions has been satisfactory, for one reason or another.
An illustration of typical prior art type spindles insofar as harp linkages are concerned is shown in U.S. Pat. No. 617,514 to Robins, which illustrates a spindle connecting the action plates and fixedly securing the discs to the action plate. A typical prior art spindle is also shown in U.S. Pat. No. 509,022 to Durkee wherein the spindle is shown to be interconnected between the action plates, and includes a tapered end which seats into a bore in one action plate, and holds the disc with the string grabbing prongs formed thereon. As shown in the Durkee patent, the chamfered surface is intended to permit rotation of the spindle relative to the one action plate, as the foot pedals are manipulated in order to rotate the discs. The Durkee reference clearly represents the typical prior art spindle, and illustrates the manner in which the friction is created as the spindle rotates. As indicated previously, over time, the chamfered portion of the spindle has a tendency to bind in the bore, and eventually, freezes in the bore area, thereby affecting the sound of the harp, and ultimately requiring replacement.
A more recent harp construction is shown in U.S. Pat. No. 1,406,347 to Clark, which again shows the action plates having a spindle interconnected therebetween, and which holds the disc with the prongs on one end of the spindle. Once again, the spindle is shown to have a tapered end which seats in a bore in the one action plate and holds the disc securely thereon. It will be observed that in the time that passed between the issuance of the Durkee patent, and the issuance of the Clark patent, no significant changes were ever made to the spindle construction.
More recent technology has in fact been applied to musical instruments, and for example, U.S. Pat. No. 3,421,398 to Whiteside does show the use of plastic bearing inserts to facilitate the movement of a hinged member on a woodwind instrument. However, the problems associated with harp linkages clearly required a solution to prevent the spindles from freezing in the bores, and for also improving the sounds emanating from the harp strings by permitting the free rotational movement of the spindles with respect to the action plates. The solution to the problem required that the spindle be freely rotatable in the bore, and it has been found to be just as important that the spindle be freely rotatable relative to the friction free bearing insert.